Many different types of winding machines are known for winding pliable strips of material such as plastic sandwich or trash bags. The common boundary between adjacent bags is often perforated to allow for easier detachment of the bags from the roll. U.S. Pat. No. 4,667,890 (the '890 patent), incorporated herein by reference, issued to the present Applicant on May 26, 1987, describes a machine for winding coreless rolls of plastic bags. The winder described in the '890 patent winds continuous strips of bags formed from a tube of plastic which has been cross sealed and perforated. To detach a bag from the roll, contained, for example in a carton, the outermost bag is pulled and the roll turns because adjacent bags are connected. When the perforation demarking the end of the outermost bag is accessible, the outermost bag is detached, and the leading edge of the succeeding bag is presented. The film which the '890 winder winds into rolls may be received directly from a bag making machine such as one described in U.S. Pat. No. 4,642,084, incorporated herein by reference, issued to the present inventor on Feb. 10, 1987, or the perforated and sealed film may have been previously made and stored. In either case the common boundary between adjoining bags is a perforated strip to allow for detaching the bags from the roll.
Interleaved bags are also well known, i.e. bags which are wound into a roll without being connected to one another. When the outermost bag of an interleaved roll is pulled, the roll turns because of the interleaving, and the outermost bag is removed from the roll because adjacent bags are not attached to one another. Because the roll turns, the succeeding bag will be readily accessible for subsequent dispensing.
Whether continuous or interleaved, the bags may be wound about a core or they may be coreless. In some applications it is desired to have bags wound on a core such as a cardboard cylinder, to provide strength to the roll. In other cases it is desirable to have "coreless" rolls to eliminate the cost and bulk associated with the core. The '890 patent describes both a coreless winder and, in the background, a winder that produces rolls with cores.
To accommodate a wide range of applications a winder should allow the user to select either a continuous or interleaved winding mode. Also, a winder should be capable of winding core or coreless rolls. To allow for ease of use, the winder should be capable of having a continuous strip of bags as its input, regardless of the type of roll being wound. Moreover, such a method and apparatus should be precisely controllable to provide for a consistent quality product.